Friday, October 7, 2011

MacGyver vs. The Accelerator Cable - A Near Stranding Saved

Who knew MG stood for MacGyver?
It started when my kids asked to go out for a joy ride.  How could I refuse?  I promised to give all three kids a turn and took off with my oldest. We got down to the bottom of a hill just around the corner from our house and the accelerator pedal seemed to lose all power. Jamming my foot against the floor board would get the engine speed up just enough to move under low power.  We limped along far enough to find a safer place and pulled over.  It was getting dark but I could see well enough under the hood to see there was no obvious catastrophe.  I also noticed that the engine was still running fine except that I couldn't get the tach above about 1500 RPM.  Odd.  It was enough to get me down the hill and across level ground, but I'll never get back up the hill at that engine speed. I start to worry about how I am going to get this thing home, and really wonder if I was just too big a sucker to notice that I'd bought a nice looking lemon.



Putting that all aside for a minute, I look back in the cockpit to see if I can see anything going wrong with the pedal itself.  Since the original design of the car was for right hand driving in England, left hand drive cars like mine have a frame that crosses to the passenger's side of the car where an accelerator cable attaches and goes through the wall into the engine bay.  Tracing that back to the throttle control attached to the carburetors, I can see that moving the pedal is having no mechanical effect on the piece that is obviously supposed to move to control gas intake.  OK, so it seems I know what's wrong but how to get back home where I might be able to fix it?

Here is where I have my "MacGyver" moment.  It occurs to me that the car has a manual choke lever to control fuel mixture for easier cold starts, which has the effect of increasing engine speed.  Since it's a different cable, it isn't affected by whatever has gone wrong with the accelerator cable.  We hop back in the car and give the choke a try.  I drop it into first gear, release the clutch, and take off at our slow limp.  Now pulling the choke full on I get the engine speed up to around 2500 RPM, which turns out to be enough to get us up the hill at about 10 MPH or so.  As we get to the top I realize I can shift up and eventually we are cruising back to home at 25 MPH.

Back in the light of the garage, I test the throttle by manually moving the control with a screwdriver and the engine revs just as expected, confirming my suspicion of a mechanical problem somewhere between the pedal and the business end of the cable.  After a few minutes of poking around I find that it appears the cable has simply slipped through the adjustable attachment near the carburetor.  I loosen the fitting with a normal socket and wrench, and pull the cable tight until the pedal inside the car is back up to its normal resting point.  After tightening the connector, everything is back to normal.  Actually, I can tell now that the pedal was already slipped some when I bought it because the new pedal height is higher by a few inches and seems more natural in use.

It's too late to take the rest of the kids out, but this is a victory. What future tricks will this car throw at me? Will my inner MacGyver be up to the challenge?  Only time will tell, so stay tuned.

2 comments:

  1. Hope it's working okay when I take my ride on Sunday!

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  2. Kevin has a theory about MGs... you live with what you can that is broken because if you fix it something worse is going to happen. Obviously this one needed to fix. He currently doesn't have working blinkers on the B... :-)

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